Under the ‘has cleared its orbital neighborhood’ and ‘fuses hydrogen into helium’ definitions, thanks to human activities Earth technically no longer qualifies as a planet but DOES count as a star.
Under the ‘has cleared its orbital neighborhood’ and ‘fuses hydrogen into helium’ definitions, thanks to human activities Earth technically no longer qualifies as a planet but DOES count as a star.
That’s a good question. Is being hydrostatic equilibrium the only physical attribute we should use for classification? Should Ceres be a planet?
I honestly don’t know. I tend to say no, as it seems to just be a lifeless rock with no geological activity. I’d love to have rules to identify that, made by planetary geologists.
But I wouldn’t want to disqualify a body with planetary characteristics like geological activity just because the space around it is busy, or it’s orbit is not in the ecliptic plain, etc.
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Ceres does appear to be active in some form with cryovolcanoes, based on the 2015 Dawn mission.
I think focus ought to be more on what the qualifications are for the minor label. What does it mean to be minor?